Ever wonder why those French fries taste so good when you are depressed?

Here’s one theory: Salt is a natural antidepressant, which might explain why we have a tendency to over-ingest it.

Kim Johnson, a psychologist from the University of Iowa, discovered that when rats were lacking sodium chloride, they did not assume their normal activities, such as eating or playing.

“Things that normally would be pleasurable for rats didn’t elicit the same degree of relish, which leads us to believe that a salt deficit and the craving associated with it can induce one of the key symptoms with depression,” Johnson said.

Johnson’s findings will be published in the July issue of Physiology & Behavior.

Johnson said the human body comes equipped “with a taste system designed to detect salt and a brain that remembers the location of salt sources,” which is why your body often craves the taste of salty foods.

"This suggests that salt need and cravings may be linked to the same brain pathways as those related to drug addiction and abuse," Johnson said.

However, before you switch from Prozac to potato chips, remember that eating too much salt can contribute to health problems such as high blood pressure and heart disease.

Click here to read more on this study.